The 21-year-old goalie is in the final season of his three-year, entry-level contract and could have become a restricted free agent after this season.
Knight was 19-9-3 with a 2.79 goals-against average, .908 save percentage and two shutouts in 32 games (27 starts) last season to help the Panthers win the Presidents' Trophy for having the best regular-season record in the NHL (58-18-6). He did not play in the Stanley Cup Playoffs when Florida was swept in the Eastern Conference Second Round by the Tampa Bay Lightning.
"Spencer is a phenomenal goaltender, as well as an exceptional athlete and person," Panthers general manager Bill Zito said. "He has thrived in his professional career, dedicating himself to his training through his first two seasons with our organization. With this extension, we are excited about the present and future of Panthers goaltending."
Knight made his preseason debut in a 4-0 win against the Nashville Predators on Monday. He made 19 saves on 20 shots in 29:56.
Selected by Florida in the first round (No. 13) of the 2019 NHL Draft, Knight is 23-9-3 with a 2.74 GAA, .909 save percentage and two shutouts in 36 regular-season games (30 starts) and 1-1 with a 2.06 GAA and .933 save percentage in two postseason games.
